A solvent is a substance that is generally capable of dissolving another substance, or solute, to form a uniformly dispersed mixture (solution) at the molecular or ionic level. Solvents are either polar (high dielectric constant) or non-polar (low dielectric constant). Water, the most common solvent, is strongly polar having a dielectric constant of 81. Hydrocarbon solvents are non-polar and are comprised of two groups, aliphatics such as alkanes and alcohols, and aromatics, which generally have a higher solvency power than aliphatics. Other organic solvent groups are esters, ethers, ketones, amines, nitrated hydrocarbons and halogenated hydrocarbons.
The chief uses of organic solvents include dissolution of coatings (paints, varnishes, and laquers), industrial and household cleaners, printing inks, and extractive processes. Because many solvents are flammable and toxic to health, there is a need to develop safer solvents for commercial use without sacrificing critical performance. A solvent described hereinafter provides high solvency performance while overcoming the toxicity issues associated with most other organic solvents.
For decades industrial and household cleaning products have been utilized to provide certain tasks such as paint removers, ink removers, degreasers, etc. Solvents are also used to clean, maintain, and prepare wood, metal, masonry, natural and synthetic fabrics, plastic components, electronic components. Although providing the needs of these many and mission-critical tasks, most solvents generally, are toxic, thus posing a threat to health and to the environment. These environmental and health threats include ozone depleting air pollutants and water pollution that threaten aquatic organisms and drinking water supplies. Many of these solvents are carcinogenic and hazardous to health in general.
Although government, industry and the community at large are all relatively well informed to the dangers of toxic solvents, the need to use such solvents has not dramatically diminished their use. Safer handling, disposal, recycling, recovery and other responsible methods of dealing with toxic substances is improving. However, the availability of safer alternative solvents is still not wide spread, especially in second and third world countries, which is due, primarily, to the high cost of the solvent alternatives and because the majority of the environmentally safer solvent alternatives do not provide satisfactory performance.
In order for an "environmentally friendly" solvent alternative to gain wide spread acceptance, a solvent should meet several criteria. First, it should provide effective performance. Second, it should be economically viable and affordable. Third, it should be widely available and, of course, it should be non-toxic to the environment generally and humans specifically.
Several alternative solvents have been introduced by industry for decades, but in general do not meet the criteria stated above. Further, many of these solvents are not completely biodegradable, just less toxic.